Traditionally, an insulating glass unit (i.e., an “IG unit” or “IGU”) has included two generally parallel glass panes held in a spaced-apart relationship by a spacer. While many standard IG units simply contain air in the between-pane space, high performance IG units are sometimes filled with insulative gas to increase the insulating capacity of the units. Whether an IG unit is filled with insulative gas or air, it is conventional in the art to provide the gas fill at a pressure that is approximately atmospheric. Filling the between-pane space of an IG unit with insulative gas advantageously increases the “R” value (i.e., the resistance to heat flow through the unit) of the resulting unit.
More recently, triple-pane IG units have become more common. A triple-pane IG unit includes three generally parallel glass panes held in spaced-apart relationship by two spacers. FIG. 2, which is discussed in greater detail below, shows an illustrative triple-pane IG unit. Air or gas is provided in the two spaces between the glass panes. Triple-pane IG units can provide increased R values compared with double-pane IG units.
Constructing triple-pane units has typically involved significant amounts of manual labor. As a glass pane is being conveyed through an IG unit assembly line, an operator adds a spacer to one of the glass pane's major surfaces. The operator then manually grasps and carries a second glass pane and leans it against the first glass pane such that the second glass pane contacts the spacer along at least one edge. The operator then adds a spacer to the outward facing major surface of the second glass pane. Then the operator manually grasps and carries a third glass pane and leans it against the second glass pane such that the third glass pane contacts the spacer along at least one edge. The three glass panes and the corresponding two spacers form a teepee configuration, which is typically conveyed to subsequent processing equipment for gas injection and/or other processes.
This method of constructing triple-pane IG units presents several disadvantages. In many instances, grasping and transporting glass panes is hard on the operator. The glass panes are often quite heavy and awkward to carry. Often, multiple operators are required because the glass panes are simply too difficult for one operator to lift. Manual lifting and carrying also significantly increases the likelihood of dropping and breaking the glass panes, making the manufacturing process more costly. Additionally, and perhaps more importantly, manual lifting and carrying substantially slows down the manufacturing process.